Generally, in order to provide superior medication delivery devices which are likely to be well received by particular groups of patients, a greater diversity in drug delivery systems have been launched to the benefit of patients. As the number of commercially available delivery systems increase, numerous different types of medication holding cartridges or containers are distributed. Most of these types of containers differ in various aspects.
Each medicament container may be filled with a particular type of medicament selected from a large variety of different medicaments, but also different kinds of the same class of medicament (e.g. rapid or long acting insulin) and different concentrations of each particular medicament may be accommodated in the containers.
Moreover, different container volumes may be introduced in order to customize each container and the associated delivery system to the needs of particular users. Variation of container volume may be provided by changing the length or diameter of the container. These modifications usually imply corresponding modifications of the dosing assembly of a medication delivery system so as to provide a particular stroke of a driving element for expelling the medicament from the container or to provide optimal dosing precision. Further discrimination between different medicament containers may be occasioned by the design requirements for each particular delivery system, such as required sliding friction of a piston accommodated in the container etc.
In order to discriminate between a larger variety of available containers, numerous container coding systems have been developed which primarily relies on the electronic reading and recognition of specific distinct containers in order to exclusively allow delivery of a specific type of a medicament by a dedicated delivery device. The following coding systems are known in the art:
US 2004/0178255 discloses an administering system where an ampoule having at least two recognition elements can be recognized by at least two associated sensors located at predetermined positions in the administering apparatus. Alternatively, the at least two recognition elements of the ampoule are detected by at least one sensor which can be moved, for example, by means of motor, past the recognition elements, to detect the relative position of the recognition elements.
U.S. Pat. No. 7,104,973 and WO 2005/075010 both relates to medical delivery systems wherein an ampoule having one or more mechanical surface structures is configured to activate switch elements of an associated administering apparatus in order to facilitate recognition of the ampoule. Both of these systems require that a particular dosing assembly is designed for the particular container associated with the dosing assembly. For a particular container carrying a specific code which is selected from a number of different possible codes, the sensor position of the dosing assembly has to be selected in accordance with that particular container. Alternatively, the dosing assembly requires a large number of sensors in order to facilitate sensing of different codes.